FIXATION OF COMPLEMENT 



lis 



dose of antigen. This procedure will be understood 

 more clearly after the Wassermann test itself has been 

 described (Fig. 10). In our own work we rely en- 

 tirely upon an imported German extract made as de- 

 scribed above, which we have found to retain its anti- 



Fig. 10. — Titration of antigen. 



Front row: Increasing quantities of antigen tested with 0.1 c.c. of known syphilitic 

 serum to ascertain optimal dose. 



Back row: Determination of anti-complementary dose of antigen. Each tube con- 

 tains 3 times the amount of antigen present in corresponding tube of front row, but 

 no serum. 



genie power almost indefinitely, and which has very 

 slight anti-complementary action. By its use we avoid 

 the rather tedious preparation and titration of anti- 

 gen, except, of course, that we make a test of anti- 

 complementary power with each new bottle, and use 

 8 



